Printing mechanism



June 3, 1958 s. GODEL PRINTING MECHANISM Filed May 9, 1955 INVENTOR. SIEGFRIED GODEL ATTORNEYS United States Patent PRINTING MECHANISM Siegfried Godel, Norwalk, Conn., assignor to Olivetti Corporation of America, New York, N. Y., a corporation of Massachusetts Application May 9, 1955, Serial No. 507,079

6 Claims. (Cl. 235-58) This invention relates to the recordation of binary information, and more particularly, it relates to digital-toanalogue conversion apparatus suitable for printing binary information in a decoded form, such as, for example, the decimal form.

In the copending application No. 505,977 of Michele Canepa, now Patent No. 2,783,464, assigned to the same assignee as the present invention, there is disclosed a system for decoding and printing binary information which includes one or more printing wheels each carrying decimal characters which are selectable to form a printed impression on a recording medium, such as a tape, in accordance with the angular position of the printing wheel. The latter in turn is determined by the binary information supplied to the system so that, in effect, the system performs two functions, that of translating the binary information into decimal form and also that of recording the same.

To properly orient the printing wheel, as disclosed in the aforementioned copending application, there is provided an indexing shaft driven through a stepping clutch in a manner whereby the indexing shaft is caused to undergo a series of angular displacements corresponding to the significances of the individual binary digits supplied; namely one, two, four, and eight. Depending on the value of each digit, whether it be zero or one, means are provided to optionally couple the printing wheel to the indexing shaft so that upon completion of the series of angular displacements, the printing wheel will have been rotated by an amount which is representative of the binary information supplied. Such amount is reflected in the particular decimal character placed in printing position relative to the tape so that movement of the printing wheel into engagement with the tape or vice versa is all that is required to then record the binary information in decoded form.

The present invention has as its object the provision of an improved drive mechanism to selectively intercouplc the printing wheel and the indexing shaft in accordance with'the value of each binary digit together with improved means to cause the printing wheel to print the binary information.

Briefly the mechanism of the present invention comprises an epicyclic gear train having a sun pinion, an internal gear concentric therewith and a pair of planetary pinions in mesh with both the sun pinion and the internal gear. Coupled to the sun pinion is the aforementioned indexing shaft and coupled to the internal gear is the printing wheel which prints on signal a decimal character corresponding to the information supplied. To optionally intercouple the indexing shaft and the printing wheel according to whether a ones or a zero digit is present in each digit column so that the printing wheel will be oriented with the proper decimal character in printing position, means are provided to selectively fix the positions of the axes of the planetary pinions in response to each digit having a value of one.

iatented June 3, 1953 ice This is conveniently achieved according to the present invention by the use of a stop gear coaxial with the sun pinion but rotatable inde endently thereof, said stop gear having rigidly attached thereto a pair of stub shafts which mount the planetary pinions. By locking the stop gear against rotation, as with a solenoid actuated pawl,

the internal gear and so also the printing wheel are placed in driven relation to the sun pinion each time a ones digit appears; that is when a switching device whose condition is indicative of a ones digit causes the actuating solenoid to become energized. Alternatively, if the value of the binary digit is zero so that the actuating solenoid is deenergized, the pawl is caused to become disengaged from the stop gear and a second pawl is caused to engage a spur gear rigidly attached to the internal gear. Thus the printing wheel will be prevented from rotating and only planetary motion of the planetary gears about the sun pinion will take place. After all the digits of a particular sequence have been operated on in this way, the printing wheel is caused to print by means of an improved printing mechanism including an actuating bar in slidable engagement with a bushing on which the printing wheel is mounted.

The novel features of the invention together with further objects and advantages thereof will become more readily apparent when considered in connection with the accompanying drawing wherein:

Fig. 1 is a perspective view of a mechanism according to the invention having portions thereof cut away to show some of the gears more clearly;

Fig. 2 is a sectional view of the mechanism of Fig. 1;

Fig. 3 is a fragmentary view in elevation illustrating the mounting arrangement of the output gear and the printing wheel of Fig. l; and

Fig. 4 is a block diagram illustrating the manner in which the indexing and cam shafts of Fig. 1 are driven.

Referring now to the drawing, and more particularly to Figs. 1 and 2, it will be observed that the mechanism of the present invention includes an epicyclic gear train having its sun pinion 11 keyed to the indexing shaft, designated as 12, and its internal gear 10 coupled to the printing wheel 13 by means of a driving spur gear 14, an output gear 16, and an idler gear 18 in mesh therebetween. Spur gear 14 is freely rotatable on the shaft 12 but rigidly attached to the internal gear 10, as with pins 15, similar pins 17 being employed to attach output gear 16 to printing wheel 13. A frame 21 provided with suitable bearings, not shown, supports indexing shaft 12 as well as a stub shaft 22 mounting idler gear 18.

In addition to sun pinion 11 and internal gear 10 the aforementioned epicyclic train has a pair of planetary pinions 24 and 25 mounted for rotation about stub shafts 26 and 27, respectively, the latter being carried by an externally toothed stop gear 31. Stop gear 31 is coaxial with sun pinion 11 but rotatable independently thereof about indexing shaft 12 whereby locking the stop gear against rotation places internal gear 10 in driven relation to sun pinion 11 through the planetary pinions 24 and 25. To lock the stop gear, there is provided a pawl 32 pivotally mounted on an arm 36 projecting from frame 21 and having its lower end pivotally connected to an actuating lever 35, as shown. Actuating lever 35 is in turn fastened to the movable element or plunger 33 of a solenoid 34 which is energized in response to each binary ones digit as will be explained more fully in connection with the description of the operation of the mechanism. A collar bracket 37 attached to frame 21 supports scienoid 34 in a generally horizontal position.

In order to bias pawl 32 so that it is normally disengaged from stop gear 31, there is provided a tension spring 41 made fast to a portion of the frame 21. Spring to pawl 44 by means of pin 42 and the other ofits ends pivotally connected to pawl 32 and to actuatihgalever 35.

As in the case of pawl 32., pawl 44 is mounted for pivotal. movement about an axis displaced from-the point where it. is acted upon, there being provided an arm 51 projecting,

from frame 21 to mount the pawl.

Referring now to Fig. 3, as Well as Figs. 1 and 2, it will: be observed that printing wheel 13 is mounted for rotation.

about a bushing 53 (Fig. 2) wherein there is formed adiametrical slot 54 (Fig. 3). stantially the same as the diameter of axial bores which are provided in each of printing wheel 13 and output gear 16, and through which there is passed an actuating bar 55' in slidable contact with the edges of the slot 54. Attached to the end of bar 55, which projects through a slot in frame 21 as shown towards the left of Fig. l, is a control lever 57 and atension spring 5%, the former having its end remote from "bar 55 connected to the plunger 61 of a solenoid 62, and the latter being fastened to a fixed Solenoid 62 is mounted on the frame by meansof a collar bracket 65 and as will arm 64'extending from frame 21.

appear, is adapted to move printing wheel. 13 into engagement with a tape 68 backed by a rubber roll or platen 67 whereby printed impressions of the decimal characters spaced around the periphery of the wheel are received by the tape.

Platen 67 and tape 68 as well as actuating bar 55 have been cut off. towards the right of Fig. l to indicate that additional printing wheel drive mechanisms like the one illustrated will. ordinarily be provided to permit the recording of a plurality of digit columns simultaneously on a single tape. In. such cases, it will be apparent to those skilled in the art that as in the aforementioned copending application, indexing shaft 12 will be common to all mechanisms and, according to the present invention, so alsowill be actuating bar 55.

To reset the mechanism of the present invention there is provided a shaft 38mounting a cam 39 for moving pawl 32 and hence also pawl 4-4 into a neutral position such that they will not register with the teeth on either stop gear 31 or spur gear 14 but will engage respectively .a key 48 and a key 49 projecting beyond the teeth on these gears. Shaft 38 is coupled to the drive motor of the system through a step clutch which maybe similar to the aforementioned step clutch associated with indexing shaft 12 except for the amount of rotation which it is adapted to produce. Both step clutches, together with a reset clutch to continuously rotateindexing shaft 12 in a forward di-- rection during the resetting operation, are illustrated diagrammatically in Fig. 4.

The operation of the mechanism of the present invention is as follows.

For each binary digit of a particular information sequence corresponding to a decimal character on the printing wheel, solenoid 34 is energized or not accordingto whether the value of the digit is zero or one, and indexing shaft 12 is then caused tobe displaced by an amountrepres'entative of the significancev of. the digit, whether it be one, two, four, or eight. Preferred apparatus for accomplishing this result, including a solenoid energizing circuit, the indexing shaft stepping clutch,-.and a timing wheel for properly synchronizing the operation of the clutch withthat of the energizing circuit may be foundin the copending application referred to previously. Assuming'for example, that the first digit of a particular sequence is arones' digit, solenoid 34 will be energized and pawl 32 pivoted. clockwise into engagement with stop gear 31. At thev same time, pawl 44 is pivoted in a clockwise direction out of engagementwith spur gear 14 so that the positions. ofthe two pawls will be opposite to that shown'in' Fig. 1..

The. length of slot 54 is sub;

Since stop gear 31 will be prevented from" rotating by pawl 32, stubshafts 26 and 27 mounting planetary pinions 24 and 25, respectively, will have their positions fixed. Accordingly, when indexing shaft 12 is rotated by an amount corresponding to the significance of the digit, namely, one, spur gear 14 is caused to rotate by a representative amount since it is also placed in driven relation to the indexing shaft by sun pinion 11, planetary gears 24 and 25, and internal gear'll. The amountby which spur gear 14 is thus rotated is in turn reflected in angular displacement ofprinting wheel 13, the latter being maintainedin driven relation to the spur gear by idler gear 18 in mesh between the latter and'output gear 16 which is made fast to the printing wheel. In particular, printing wheel 13 will be displaced by an amount equal to the spacing between characters so that the decimal numeral one on its periphery is placed in printing position relative to the tape 68.

115,; now, the next binary digit of. the sequence is zero, solenoid 34 will be. deenergized so that pawls 32. and 44 are caused to assume the positions shown in the drawing, namely, with pawl 44 engaging spur gear 14, but with pawl 32 out of engagement with stop gear 31. In this case;;sp ur-i gear 14 and so also. the printing wheel. will be prevented from. rotating, and the only motion that will take place. when. indexing; shaft 12 is displaced by an amount corresponding tothe significance of the digit, namely, two, isv planetary motion: of gears 24 and 25 aroundthe sun pinion. 11. Should the next binary digit be acne, howevenprinting wheel 13 will be further displacedby an-amountcorresponding to four decimal characters,,and soforth. In thisrway the angular position of thepr-inting wheel is caused to reflect thelbinary information digit bydigit until. all of'the digits of the sequence decimal character'comesl in. contact with the tape.

have. been operated'on.

At such time, the decimal character on the periphery of printing wheel13 corresponding to. the binary information will be. placediin printing; position. To cause the printing.- wheel: to print, solenoid 62 is energized momentarily in any suitable; manner as with they aferomentioned timing wheel; moving actuating bar 55 towards the tape and. with it the printing wheel 13 until the proper Solenoid 62 is then deenergized and the printing wheel returnedtoitsnormal position out of contact with the tape under the influence of spring SSJWhich-urges actuating bar 55 in the opposite direction.

The manner inwhich the mechanism is reset to place itinrconditiontoreceive a newsequence of binary digits is as: follows. Cam 39 attached toshaft 38 is rapidly rotated approximately 180 by means of the step clutch associated therewith causing pawls 32 and 44 to assume positions sufiiciently close to stop gear 3.r andspur gear 14, respectively, that they will engage only the keys 48" and 49, projecting therefrom. By'then rotating indexing shaft 12 in a forwarddirection through actuation of there'set clutch, projections 48 and 49 will come in contact with p'awls 32 and 44, respectively, the sum of the motions of the latter gears being equal to the sum of their motions inresponseto the previousbinary digit sequence. This effectively placesthe. gears attheir. starting positions so. that the-mechanism. will. be-in condition to receive the next sequenceofbinary digits.

it. will be apparentto those skilled in the art that the herein disclosed mechanism will also operate on other than numerical information and maybe readily adapted to printletters rather thannumbers. Likewise other arrangementsfor causing the printing wheel. to print may to be limited only by the scope of the appended claims.

What is claimed is:

1. In a system for decodirzg and printing binary information constituted by a sequence of individual binary digits which includes an indexing shaft to provide a series of angular displacements corresponding to the values of the individual binary digits in said sequence, and a printing wheel carrying angularly spaced printing characters, each representative of a respective sequence, the combination with said indexing shaft and said printing wheel of a printing wheel drive mechanism to selectively intercouple the indexing shaft and the printing wheel in accordance with the values of the digits contained in the sequence thereof, said printing wheel drive mechanism comprising: an epicyclic gear train having a sun pinion coupled to said indexing shaft, an internal gear coupled to said printing wheel, and at least one planetary pinion in mesh with said sun pinion and said internal gear; and means operable in response to each digit in said sequence to fix the position of the axis of said planetary pinion whereby said internal gear and said printing wheel are caused to rotate with said sun pinion and said indexing shaft, the total amount of said rotation being representative of said binary information.

2. In a system for decoding and printing binary information constituted by a sequence of individual binary digits which includes an indexing shaft to provide a series of angular displacements corresponding to the values of the individual binary digits in said sequence, and a printing wheel carrying angularly spaced printing characters, each representative of a respective sequence, the combination with said indexing shaft and said printing Wheel of a printing wheel drive mechanism to selectively intercouple the indexing shaft and the printing wheel in accordance with the values of the digits contained in the sequence thereof, said printing wheel drive mechanism comprising: an epicyclic gear train having a sun pinion coupled to said indexing shaft, an internal gear coupled to said printing wheel, and at least one planetary pinion in mesh with said sun pinion and said internal gear; an externally toothed stop gear coaxial with said sun pinion but rotatable independently thereof; mounting means for said planetary pinion rigidly attached to said stop gear; and means to lock said stop gear against rotation in response to each digit of selected value in said sequence whereby said internal gear and said printing wheel are caused to rotate with said sun pinion and said indexing shaft, the total amount of said rotation being representative of said binary information.

3. A printing wheel drive mechanism according to claim 2 wherein said last-named means includes a solenoid actuated pawl adapted to engage said stop gear.

4. A printing wheel drive mechanism according to claim 3 including a driving gear mounted for rotation with said internal gear and a second solenoid actuated pawl adapted to engage said driving gear.

5. In a system for decoding and printing binary information constituted by a sequence of individual binary digits which includes an indexing shaft to provide a series of angular displacements corresponding to the values of the individual binary digits in said sequence, and a printing wheel carrying angularly spaced printing characters, the combination with said indexing shaft and said printing wheel of printing Wheel drive mechanism to selectively intercoupie the indexing shaft and the printing Wheel in accordance with the values of the digits contained in the sequence thereof, said printing wheel drive mechanism comprising: an epicyclic gear train having a sun pinion coupled to said indexing shaft, an internal gear concentric about said sun pinion, and at least one planetary pinion in mesh with said sun pinion and said internal gear; a driving gear mounted for rotation with said internal gear; an output gear in driven relation to said driving gear, said output gear being rigidly attached to said printing wheel; a stop gear mounted coaxially with said sun pinion but rotatable independently thereof; a stub shaft rigidly attached to said stop gear mounting said planetary pinion; a pair of pivotally mounted pawls adapted to engage said stop gear and said driving gear, respectively; a control lever pivotally attached to said pawls; and a solenoid having its movable element attaches. to said control lever to move the latter between a first position wherein one of the pawls is caused to engage the teeth on said stop gear and the other of said pawls is disengaged from said driving gear, and a second position wherein said one of the pawls is disengaged from said stop gear and said other of the pawls is caused to engage said driving gear, said solenoid being selectively energized and deenergized to place said control lever in said first and second positions according to the successive values of the digits in said sequence.

6. A p2 Wheel actuating mechanism according to claim 5 including a stationary bushing for mounting said output gear said printing wheel, said bushing being provided with a diametrical slot; and an actuating bar projecting through said slot to move said printing wheel into a printing position.

References Cited in the file of this patent UNITED STATES PATENTS 

